Revista Española de Cirugía Oral y Maxilofacial
Print version ISSN 1130-0558
SOLE, Pedro and REININGER, David. Analysis of the vertical position and depth of the external pin in orthognatic surgery. Rev Esp Cirug Oral y Maxilofac [online]. 2012, vol.34, n.2, pp.47-50. ISSN 1130-0558.
Introduction: To vertically reposition the maxilla it is necessary to have an attachment called the external pin, which allows for measurements to be taken during surgery. The sites most often used to insert the pin are the nasion and glabella, but the question remains as to which of these two sites is the optimum as regards increased retention, stability, and less chance of intraoperative and postoperative complications. Objectives: The objective of this study is to analyze the best place for the introduction of the pin from an anatomical point of view, and propose a universal unique location in both vertical and sagittal directions that will be usable for all types of patients. Materials and methods: We performed an exploratory study, randomly selecting 99 patients aged 21 to 27 years, all of whom were dental students at the University of the Andes, Santiago de Chile. They all had a lateral radiograph, measuring the bone and soft tissue thickness at nasion and glabella level. The patients were grouped by sex and biotype to assess similarities in the thickness measurements. Results: There were no significant differences in the thicknesses of the nasion and glabella in the various groups. Greater bone and soft tissue thickness was found at nasion level (a total minimum thickness of 13.83mm) than in the glabella, 6.37mm. Conclusion: Due to the wide range of thicknesses it was impossible to determine a single value standard for the introduction of the pin, with the nasion being considered the site of choice.
Keywords : Vertical maxillary repositioning; Le Fort I osteotomy; Predictability of maxillary repositioning; Orthognathic surgery; Maxillary osteotomy.